Our lab supports the first HU iGEM team. The students set out to solve the microplastic problem by creating green algae capable of degrading plastic. Follow their updates. For more info visit www.igem.hu-berlin.de, to become a sponsor or to get involved contact igem@chlamy.de.

Here is nice feature from the rbb about the chlamylicious iGEM project:

(c) rbb

The Chlamy group in the Hegemann lab is interested in the characterization of known but so far uncharacterized photoreceptors and newly discovered ones. Many of these photoreceptor proteins were found in the model alga Chlamydomonas reinhardtii. In addition to in vitro electrophysiological and spectroscopic characterizations, we aim to decipher the photoreceptor network in Chlamydomonas.

Our incentive is to delete the photoreceptors separately and in total and to specifically modify them to understand their biochemical function and physiological role.

Project Background

DNA double-strand breaks (DSBs) in the gene of interest are prerequisites for capitalizing the cells own DNA repair mechanism that ultimately results in gene deletion or modification. Widely used programmable site-directed DNA-cleaving enzymes are zinc-finger nucleases (ZFN), transcription activator-like effector nucleases (TALEN) and the CRISPR/Cas9 system (Clustered Regularly Interspaced Short Palindromic Repeats). Cells have different mechanisms to cope with DSB. Repair of DNA lesions by non-homologous end-joining (NHEJ) is error-prone and lead to unpredictable modifications on the target site. In contrast, homologous recombination (HR) allows the defined deletion (knock out), repair (rescuing), tagging (knock-in) and modification of selected genes. However, HR is an extremely inefficient process in most eukaryotes including algae, plants, and animals

Targeted genome editing with programmable nucleases

In Chlamydomonas reinhardtii, HR efficiency was greatly enhanced by introducing double-strand breaks with the help of two engineered zinc-finger nuclease (ZFN) proteins (Sizova et al. 2013).

Now, we further optimized the protocol to target genes also in motile strains and adapted to use the CRISPR/Cas9 system (Greiner et al. 2017).

Furthermore, we are looking for genes influencing the transformation, gene targeting efficiency, and DNA repair pathways, either by deletion or suppression of relevant proteins. The understanding of the underlying DNA repair mechanisms is fundamental to exploit this system and use it for precise genome editing experiments.